1. Field of the Invention
The present invention pertains to a light guide support mechanism, and more particularly to the support of a light guide having a rod-like configuration.
2. Description of the Related Art
Conventionally, rod-shaped light guides have been employed as light guides, i.e., light transmission elements, for various uses. These rod-shaped light guides are sometimes used for illumination, using their ability to emit light having an almost uniform luminance distribution via reflection inside the light guide.
Where a rod-shaped light guide is used for illumination as described above, in order to minimize the loss in light transmission, in some cases, a silver-deposition surface is formed on the outer circumference of the rod-shaped light guide, so that light emission from the outer circumference is prevented. However, light cannot be transmitted with high efficiency using this method because there is light transmission loss during reflection inside the light guide due to the internal reflective surface.
As an optical material offering highly efficient light transmission, optical fiber constructed of two layers having different densities is generally known. While optical fiber has the advantage of pliability, it has the disadvantages that (i) since it has a small diameter, the surfaces for light to enter and come out of the fiber are very small, and (ii) while the fiber may be used in a bundle, it is expensive to do so.
On the other hand, if a rod-shaped light guide is supported such that it is suspended in air, high-efficiency light transmission based on total reflection taking place due to the difference in density inside the rod-shaped light guide is possible, just as with optical fiber.
However, in order to support the rod-shaped light guide, it is necessary to make contact with the rod-shaped light guide, and the area of contact will not have total reflection, thereby causing a loss in light transmission.